Section 111 Model 162B
Paragraphs 3-7 to 3-23
3-7. VERNIER. The VERNIER control provides 3-17. ALTERNATE. In this mode the two channels
continuous adjustment of the deflection sensitivity, are presented on alternate sweeps. For accurate
and allows the display to be set to any arbitrary height. time or phase comparisons, use an external triggering
Minimum sensitivity can be set to at least 50 v/cm. signal.
3-8. SENS. CAL. This front panel screwdriver
adjustment allows the calibration of the Model 162B 3-18. DIFFERENTIAL OPERATION.
to be set using an external voltage standard or the
3-19. Since both inputs are fed to the Channel A
calibrator of the Model 160B/170A. A step-by-step amplifier in this mode of operation, only the difference
procedure for this adjustment is outlined in figure 3- 2. between the two inputs will be displayed on the screen.
Therefore any signal on both channels which is equal
3-9. BAL. The BAL. control balances the amplifier in phase and amplitude (common mode signal) will be .
so that no vertical shift of the trace occurs when the
VERNIER control is operated. A step-by-step pro- rejected. Use differential mode where measurements
cedure for BAL. is outlined in figure 3-2. are made in the presence of hum or other unwanted
pickup. A step-by-step operating procedure for A-B .
3-10. VERTICAL POSITION. The VERTICAL POS- is outlined in figure 3-5.
ITION control has a range of *9 cm., so that offscreen Note
portions of the trace may be brought into view. For greatest rejection of common-mode sig-
nals, set both channels to the same sensitivity.
3-11. POLARITY. The POLARITY switch reverses
the polarity of the trace on the screen. Thus, in the
-UP position, a negative voltage causes an upward 3-20. INPUT CONSIDERATIONS.
deflection.
3-21. ACCESSORY PROBES. To preserve the band-
width capabilities of the Model 162B, certain precau-
3-12. SINGLE TRACE OPERATION. tions must be observed. To avoid circuit loading and
resultant waveform distortion, accessory probes may
3-13. The vertical presentation switch allows selec- be used to increase the input impedance. The lOOOlA
tion of either Channel A or Channel B for presentation Probe supplied with the Model 160B/ 170A Oscilloscope
on the screen. For step-by-step operating procedure, presents an input of 10 megohms shunted by 10 pf
refer to figure 3-3. and may be used over the 30 megacycle bandwidth of
the Model 162B. When using the probe multiply the
SENSITIVITY setting by 10.
3-14. DUAL TRACE OPERATION.
3-22. When using the lOOOlA (AC-21A) or other
3-15. The vertical presentation switch also selects accessory probes, it is necessary to compensate the
either of two modes of dual trace operation, CHOPPED probe for the input impedance of the amplifier. With-
or ALTERNATE. For step-by-step operating pro- out compensation, the probe will not divide accurately
cedure refer to figure 3-4. at high frequencies and waveforms will be distorted.
For compensation adjustment refer to the lOOOlA
3-16. CHOPPED. In this mode of operation the two (AC-21A) operating note.
channels are electronically switched at approximately
200 kc on a single sweep. Accurate time difference 3-23. AMPLIFIER OVERLOAD CAPABILITY. In
or phase comparisons may be made in this mode, certain situations it may be desired to observe with
since both signals occur on the same sweep. However, increased sensitivity a small part of a waveform. A
this mode is intended to be used where the input signal as large as 18 cm (3 vertical screen diameters)
frequency is much lower than the rate at which the may be applied to the input without causing noticeable
channels are switched. distortion.
3- 2 01558-1 |
ACEC
